My recent Red Cross First Aid / CPR course also taught the FAST criteria - for Arms, have them raise both arms, because often in a stroke, one side might not work (or they might not be able to control one even if they can lift it.)
The biggest things you can do to prevent stroke are to get at least occasional physical checkups, and make sure your blood pressure isn’t too high. For mild levels of high blood pressure, the medicines don’t have serious side effects and are really inexpensive (e.g. $5/month), so don’t just say “Oh, I exercise and don’t use too much salt” - take them. For seriously high blood pressure, go listen to some of Penn Jillette’s videos from the past year about having extreme numbers (over 200!), taking as many as six medicines at a time, losing 100 pounds in a hurry because his doctor got him too.
If you have sleep apnea, that’s also a potential stroke and heart attack risk. I used to snore loudly when I was young and thin, and when I got older and fatter I started getting some apnea problems as well. CPAP machines are a bit annoying, but not that bad, and having my wife shake me to stop my snoring several times a night had been annoying too 
There are other alternatives (some people are helped by mild surgery on the nose or throat, or by dental appliances that prop your mouth open at night, Pro-Vent nose strips do a partial job but are better than nothing.)
I’d rant just as much about blood sugar, but mine’s always been amazingly normal, and as a vegetarian, my cholesterol’s low, but my blood pressure has been at least mildly high since high school.
